This invention relates generally to farm machinery and, in particular, to apparatus and a method for controlling multiple functions of an implement such as an agricultural baler.
Farm tractors of today typically have one or two independent hydraulic circuits which can be connected to the hydraulic lines of an implement to control multiple functions of the implement while it is attached to the tractor. In the past, when attaching an implement to an open cab tractor which has only one hydraulic circuit, many functions of the implement were controlled manually by the tractor operator using devices such as pull ropes and crank arms.
More recently, however, electrical servo valves have been utilized to control implement functions. These servo valves are undesirable because they are expensive and unreliable. Furthermore, they are not compatible with some tractors and also result in complex wiring on some tractors. Electric linear actuators have also been used to control implement functions but they lack reliability and are too costly.
Open cab tractors have included selector valves in their hydraulic circuits to enable the tractor operator to control two independent functions of an implement by manually shifting a selector valve to the desired position. However, these selector valves are undesirable on tractors with enclosed cabs because it is difficult to locate them inside the cab while they are still hooked into the hydraulic circuit of the tractor. Furthermore, these selector valves are not desirable because it is easy for the operator to forget what position the valve is in, and there is usually no logical mounting location for the valve in the enclosed cab of a tractor.